检测属性传进来值:
	类型、默认值

	React v 1.5x之前 ， React.PropTypes

	之后，需要单独库文件:  prop-types

	class Title extends Component{
	    static propTypes ={	//检测类型
	        name:PropTypes.string
	    }
	    static defaultProps = { //默认值
	        name:123
	    };
	    render(){
	        return <h3>{this.props.name}</h3>
	    }
	}
	---------------------------------
	class Title extends Component{
	    render(){
	        return <h3>{this.props.name}</h3>
	    }
	}
	Title.propTypes ={	//检测类型
		name:PropTypes.string
	}
	Title.defaultProps = { //默认值
		name:123
	};

	PropTypes.string
	PropTypes.number
	PropTypes.bool
	PropTypes.func
	PropTypes.array
	...


<script type="text/babel">
    let {Component} = React;

    class Title extends Component{
        static propTypes ={
            name:PropTypes.string
        }
        static defaultProps = {
            name:123
        };
        render(){
            return <h3>{this.props.name}</h3>
        }
    }
    /* Title.propTypes={
        name:PropTypes.string
    }; */

    ReactDOM.render(
        <Title />,
        document.querySelector('#root')
    )
</script>